Jim Laurent at Sun Microsystems composed a chart comparing Solaris 10 to Linux for his boss, Bill Vass, chief operating officer of Sun's federal business unit. When Vass posted the chart for public viewing, Laurent commented on it in his personal blog in late December.

Laurent said Solaris has certain advanced technical features, such as Dynamic Tracing, which give it an advantage over Linux, along with its ability to run on more versions of hardware. He acknowledged his partisanship in a posting to his blog.

"As the primary author of the chart, I felt that I should come out from behind the veil of my COO," Laurent said. "Admittedly, the list is composed from the point of view of a long time (12 years) Sun employee and Solaris ambassador." Laurent, a Solaris system engineer, is Sun's operating system ambassador at Sun's federal business unit in McLean, Va.

Dynamic Tracing or DTrace gives Solaris 10 users the ability to plant metrics in the operating system kernel that will report on both kernel activity and how an application is running. The probes or programmable sensors can be scattered through a system to record, for example, the time stamp of when a request for data from storage is submitted and when the results come back, telling the user whether he's identified a performance trouble point.

Laurent also listed ZFS or Solaris 10's 128-bit file system and Solaris' approach to virtualization, Containers.

His list includes Solaris' many security features, including Secure by Default, Cryptographic framework, digitally signed executables, and Solaris Trusted Extensions.

His equivalent list for Red Hat Enterprise Linux 5 it is a short one. For example, he cites Global File System, RHEL 5's clustering file system, but ignores the other file systems supported by the RHEL kernel, such as ext3. When Sun wanted to compare its ZFS file system to Linux in a June 2007 white paper, however, it chose to highlight ext3 in the comparison.

Other advanced features he lists for Linux include SE-Linux multilevel security, Distributed Lock Manager, and Block level storage encryption.

Solaris 10 comes out ahead on the supported hardware systems. It runs on the Sparc and UltraSparc processor platforms as well as x86, while Linux is designed as an x86 instruction set system. Linux has also been ported by IBM to its Power chip architecture and z mainframe system. By Laurent's count, Solaris leads the way, running on more than 900 hardware systems, compared with 329 for RHEL 5.

Laurent offers a direct cost comparison as well. He views a RHEL 5 subscription as the equivalent of Sun technical support for Solaris 10, and cites the following figures: Basic support for a two-socket or two-way server (that's four cores in a dual core system) is $720 for Solaris and $799 for RHEL 5. Premium support for the Solaris is $1,080 versus $1,299 for Red Hat.

But that comparison may assume that a Red Hat subscription is only technical support. Red Hat subscriptions include other features, cited here, such as the Red Hat Network, which supplies automated release deliveries and updates and system management capabilities for many copies within an enterprise. Lauent's cost comparison chart is listed at: http://blogs.sun.com/jimlaurent/entry/solaris_10_costs_less_than.

While listing Solaris Containers, Laurent does not mention in his Linux list RHEL 5's support for the Xen open source hypervisor. Hypervisor and Container virtualization are two different things and it's up to the user to decide which is better. Container virtualization is basically partitioning the hardware resources under one copy of the Solaris operating system instead of multiple virtual machines. A hypervisor approach lets multiple x86 operating systems run above the hypervisor, such as Windows and Linux, allowing different applications to be accommodated on the server.

Laurent offers another comparison, the length of vendor support for a given version of the operating system. With Solaris 10, that's 12 years. For RHEL 5, it's seven, Laurent wrote.

After posting his information, Laurent aired the fact that an experienced Unix user, Mike Gerdts, charged that he had overlooked the fact that OpenSolaris is a recognized open source project, but Solaris 10 "is not."

Laurent responded: "Solaris 10 is still in a transitional state in the open source process. While I will admit that not all of the code is released, it is still light years ahead of AIX, HP-UX and some other products in that the community can look at the code and contribute to advanced technologies such as DTrace, ZFS and others that eventually get back ported into Solaris 10."

In a similar manner, many features that are included in the Linux kernel, such as Kernel Virtual Machine, a second form of virtualization with Linux, are not yet back ported into RHEL 5.